Draftman&#39;s device



Jan. 4, 1949. R. M. BROWN DRKFTSMANS DEVICE Filed Sept. 9, 1947 GOALSHIPMENTS TONS 80 Inventor Bane M Brown his AHo neY Patented Jan- 4,1949v nnu'rmms nrzvrcn Russell M. Brown, Prince Georges County, Md.Application September a 1947, Serial No. 773,004

8 Claims.

My invention relates to improvements in plotting devices for draftsmenin which is utilized a ruler provided with a plurality of graduatedscales differing from eachother and triangular in cross section. Ipreferably use a ruler of the type commonly known as an architect's,engineer's, or a chain scale. For convenience of reference such rulerwill hereafter be referred to in this specification as an engineer'sruler.

Objects of my invention are to produce a universal plotting device whichis especially useful in making charts; to produce an adjustable holderfor an engineer's ruler or for a French curve one side and an end ofwhich is formed as a right angle; to produce a drawing instrumentembodying an engineers ruler by means of which a user can quickly andaccurately divide a given space into a plurality of equal spaces; and toproduce a drafting device which is eilicient, simple in construction,and cheap to manufacture.

The novel features which I believe are characteristic of my inventionare set forth with par-' ticularity in the appended claims. Theinvention itself, however, as to both its organization and method ofoperation will best be understood by reference to the descriptionwhichfollows hereunder taken in comunction with the drawing forming apart of my disclosure and in which:

Figure 1 is a plan view of one form of my invention illustrated in aposition of use with respect to a T-square and a conventional drawingboardon the latter of which is shown a line chart.

Figure 2 is a plan view of another form of my invention in which isutilized a French curve provided with a straight edge;

Figure 3 is a side elevation of a fastener or clamp for attaching anengineer's ruler to the adjustable arm forming a part of my holder.

Figure 4 is a modification of the device illustrated by Fig. 3.

Figure 5 is a side elevation of a constructural detail illustrating aprotractor clip mounted adjacent an end of the slide bar of my holder.

Figure 6 is a modification of the element illustrated by Fig. 5.

Figure 7 is an end view of the slide bar of my holder.

Similar numerals refer to similar parts throughout the several views.

Essentially, my invention consists of an engineers ruler in combinationwith an adjustable curve may be mounted. In Fig. 1 my device is 2 shownas lying on a drawing board B of the usual construction andin slidableengagement with a T-square S in position of use for drawing a graph onthe line chart 0.

As hereinbefore stated, the ruler may be of a conventional type. Myholder however, consists of a slide bar 4 which may be of any suitablematerial and cross sectional shape, although in the embodimentillustrated I have selected a channel bar to minimize weight.Intermediate the ends of the bar and shiftably mounted thereon is anadjustable arm-5 upon one end of which is pivoted a fastener or clamp 6.Likewise, a protractor clip 1 is pivoted to one end of the bar 4. Thesetwo devices 6 and I detachably engage an engineers ruler R. Y

From Figs. 1 and 5, it will be observed that one end of the clip issemi-circular in shape, is provided with an arrow, and is pivoted to theslide bar and may be clamped thereto by means of a knurled nut 8. Inorder to enable the device to be used as a protractor, the slide bar isprovided with a protractor scale adjacent to such arrow, graduated from0 to degrees.

The clip is fabricated of a flat piece of spring metal and is shaped atone end to form an open triangle in cross section to conform to thecross sectional shape of an engineer's ruler, and inwardly projectingrunners 9 are formed integral with the legs of such triangle to snuglyengage the grooves or concavities ordinarily formed in such ruler.

The arm 5 is shiftably mounted on the slide bar in any suitable manner,a convenient way being to provide the arm with a longitudinal slot illand aflix the same to the bar by means of a clamping screw l I extendingthrough the slot.

In order to indicate the angle to which the curve is adjusted withrespect to the slide bar, the arm 5 is provided with a longitudinallyextending degree scale l2 graduated from 0 to 90 degrees andwith'corresponding indexing notches ll spaced 15 degrees apart, startingwith 0 degree, the slot extending between the scale and notches.Inasmuch as the most common angles used in drafting are 15, 30, 60 and90 degrees, it will be obvious that speed in using my instrument maybeattained by employing the notches in adjusting the angle of the'curve.

The fastener or clamp 8 is mounted on the uppermost end of the arm and,except for the manner of mounting, it may be of any variety so long asit is quickly detachable. In the form shown it consists of two jaws Hand I5 biased toward each other by means of a cylindrical spring l8through which the Jaws extend. One 01 the jaws I4 is movable and carriedby the spring and the other fixed, the fixed jaw being provided with aright angular extension upon which is mounted a screw threaded stud l'lextending through a hole in the end of .the arm, whereby the clamp maybe swung through a wide arc with respect to the arm and locked theretoby means or a knurled nut l8.

Instead of using a clamp, the device illustrated by Fig. 4 may beemployed. This device is fabricated of a single piece of sheet metal,one end of which is shaped to form an open trapezoid conforming to thecross section of the ruler R and the other end of which is adapted to bemounted on the arm by the same means as the clamp. A bodily shiftableplate i8 is mounted between the legs of the trapezoid by means of ascrew 20 to which the plate is swiveled and which has screw threadedengagement with one leg of the trapezoid. The shiitable plate and thecoaeting leg of the triangle are also provided with parallel runners 9adapted to snugly and slidably engage the grooves or concavities of theruler.

Similarly, instead of using a protractor clip, it is within the spiritof my invention to employ an equivalent element such as is illustratedby Fig. 6. This device is designed to be pivoted on the bar in the samemanner as the clip and consists of a fiat piece of metal 2| having a cutout portion to provide a finger 22. Lugs 23 are formed on the elementand extend at right angles thereto intermediate the ends thereof.Fixedly mounted in the lugs is a spring finger 24 oppositely disposed tothe finger 22 and spaced therefrom suinciently to enable both fingers toengage the grooves or concavities of the ruler.

In Fig. 2 I have illustrated my holder in connection with a combinedstraight edge and French curve 24 one end of which is pivotally anddetachably connected to the slide bar by means of a quickly detachablelocking device 25 extending through a suitable hole 25 intermediate theends of the bar. The longer arm of the device is attached intermediateits ends to the end of the arm by means of a stud and nut device l8similar to the one heretofore described.

My combined holder and ruler is especially useful in making drawingscharts of all kinds, and

one of its novel features is the speed and accuracy with which either ofthe six scales on an engineer's ruler may be used to locate points on achart by merely sliding my device along a T-square or other straightedge without any other manipulation.

If the main zero point on the ruler is placed I anywhere along and overthe chart abscissa and the ruler held in that position but slanted sothat any other main division point on it is over any horizontal chartline, then dots placed on the chart directly opposite the subdivisionsand main points on the ruler will constitute coordinates. Vertical andhorizontal lines drawn through such coordinates parallel to the chartordinate and abscissa, respectively, will be equally spaced apartvertically and horizontally, and the number of spaces will depend uponthe number of subdivision points on the scale. If smaller spaces aredesired, it is necessary to use a ruler provided with a scale havingsmaller subdivisions. It is just at this point that the flexibility andversatility of my device is demonstrable.

Instead of being limited to the use of a ruler having only a singlescale and, consequently, a fixed number of subdivisions between its maindivision points, I use a ruler having six scales each provided with adifferent number of subdivisions. For example, an engineers rulerbetween its zero point and its first main division, is provided with sixdifferent scales divided into 10, 20, 30, 40, 50, and subdivisions,respectively. Consequently, for all practical purposes any number ofsubdivisions can be accurately plotted on a chart by selecting anappropriate scale, 0! course, this can be done by manually manipulatingthe ruler, but without the speed of operation and accuracy of resultsattained when such a ruler is used in conjunction with my holder.

One use of my invention is illustrated by Fig. 1. It is assumed that thenumber of tons of coal shipped from a particular mine during the years1920 to 1924, inclusive, were 46 tons in 1920; 16 tons in 1921; 58 tonsin 1922; and 36 tons in 1924, or any multiple thereof. An appropriatechart C having grid lines is selected in which the curve shown isplotted with tons as the ordinate against years as the abscissa. The 10scale on an eng'ineers ruler should preferably be used because itssubdivisions will exactly indicate the numbers of tons involved. Theruler is then mounted in the holder and the latter placed on a drawingboard against a T-square with the 0 point of the ruler over the abscissaand any main division point of the ruler over any horizontal line on thechart. It will be seen that by merely sliding the device tothe left onthe T-square until the subdivision point indicating 16 on the ruler isdirectly over the 1921 grid line, a dot placed on the chart at thatpoint will represent 16 tons of coal shipped during that year. The otherdata is indicated in the same way, and the dots on the chart are thenconnected by a line to complete the graph. Suppose, however, that thescale of the chart is 0 to 360 tons and tons were shipped during theyear 1923. In that case the 10 scale on the ruler could not be usedbecause its main divisions are not divided into the appropriate numberof subdivisions. Consequently, the ruler would be mounted in the holderso that the 60 scale would face the draitsman and then the pointindicated on the chart as above described.

It will be observed that although the use of the arm 5 is desirable toprovide'rigidity, nevertheless my holder is capable of practical usewithout utilizing it, not only for drawing line charts and otherdrawings but also as a protractor, by merely clamping the ruler inposition by screwing down the nut 8 to lock the protractor scale I tothe slide bar 4.

I am aware of the fact that plotting devices employing holders for flatrulers and designed to be slid along a straight edge have heretoforebeen proposed, but such devices required the holder to be equipped withspecial devices for mounting the same on a straight edge or foradjusting them on a straight edge, or required the holder, board andstraight edge to be formed as a more or less unitary structure; and notany of them attained the versatility made possible by employing a rulerprovided with a plurality of different scales, Accordingly, I claim asnew and desire to secure by Letters Patent:

1. In an instrument of the kind described, the combination with a holderof an engineers ruler triangular in cross section and provided withgrooves along the sides thereof, the said holder comprising a slide bar,a protractor clip pivoted to the end of said bar and provided withrunners engaged in grooves of said ruler, an adjustable arm having alongitudinal slot therein and a clamp pivoted on an end thereof, thesaid clamp being provided with' runners engaging grooves in said ruler,a locking device carried by said am for locking said clamp to said arm,and an additional locking device carried by said bar for locking the armto the bar in various-positions of adjustment.

2. In an instrument of the kind described, the combination with a holderof a ruler triangular in cross section and provided with a plurality ofscales, the said holder comprising a slide bar, a protractor clippivoted to the end of said bar and provided with means for detachablyengaging said ruler, an adjustable arm having a longitudinal slottherein and a clamp pivoted on an end thereof, the said clamp beingprovided with means for engaging said ruler, a locking device carried bysaid arm for locking said clamp -to said arm, and an additional lockingdevice carried by said bar for locking the arm to the bar in variouspositions of adjustment.

3. A holder adapted for use with an engineers ruler triangular in crosssection and provided with grooves along the sides thereof comprising aslide bar and a protractor clip pivoted to an end of said bar, said cliphaving runners adapted to engage the grooves in said ruler.

4. A holder according to claim 3 including a locking device associatedwith said bar and said clip for locking the clip in any position ofangular adjustment with respect to said bar.

5. A holder adapted for use with an engineer's ruler triangular in crosssection and provided with grooves along the sides thereof comprising aslide bar, an adjustable arm having a longitudinal slot therein and aclamp pivoted on an end thereof, the said clamp being provided withrunners engaging the grooves in said ruler, a locking device carried bysaid arm for locking 6 said clamp to said arm, and an additional lookingdevice carried by said bar for locking the arm to the bar in variouspositions of adjustment. 6. A holder adapted for use with an engineersruler triangular in cross section and provided with grooves along thesides thereof, comprising a slide bar, an adjustable arm having alongitudinal slot therein and a clamp pivoted on an end thereof, thesaid clamp being provided with runners adapted to engage the grooves insaid ruler, and a locking device carried by said bar for locking the armto the bar in various positions of adjustment.

RUSSELL M. BROWN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 146,673 Haslett Jan. 20, 1874223,727 Halley Jan. 20, 1880 695,747 Lydick Mar. 18, 1902 830,322 HodgeSept. 4, 1906 1,142,368 Row June 8, 1915 1,209,855 La Follette Dec, 26,1916 1,394,088 Heller Oct. 18, 1921 1,396,806 Beais Nov. 15, 19211,661,095 Rowe Feb. '28, 1928 1,809,058 Miner et al. June 9, 19312,060,686 Niemi-c Nov. 10, 1936 2,190,327 Clerk Feb. 13, 1940 2,082,758Weeks et a1. Aug. 14, 1945 FOREIGN PATENTS Number Country I Date 11,693England 1891 135,646 England Dec. 4, 1919

